SSD's are WAYYYYY faster. The system loads up in under 20 seconds, iTunes opens in 1 second etc. Everything is way snappier.
The blazing speed of the ssd and the capacity of the hdd.
Yes it's easily the best upgrade for the vast majority of Mac users. People get excited about faster RAM, CPUs, and graphics cards, but its the hard drive that has been dragging our systems downs forever.
Thanks. That explains a lot. Now I wish I was able to afford the 512GB SSD in my MBP